EFFECT OF INITIAL CONDITIONS ON CHARACTERISTICS OF TURBULENT FAR WAKE

A study has been made of turbulent vortices behind various wake-generating bodies (circular, triangular and square cylinders and a screen of 50% solidity). Using a rake of eight X-probes which was aligned in the plane of mean shear, velocity data have been obtained in the far wake at sufficiently large Reynolds numbers. Profiles of the Reynolds stresses show measurable differences in the wakes from different generators. Correspondingly, some aspects of the organized motion, e.g., the circulation of the vortices and their coherent contributions to the Reynolds stresses, are sensitive to the initial conditions. The difference is especially noticeable between the wake of the screen and the solid-body wakes. For the screen, the far-field vortices are highly similar to the near-field ones. For the solid-body wakes, the far-field vortices bear little resemblance to the near-field vortices.